1. Field of the Invention
The present disclosure relates to a backlight unit, which can improve the image quality of a display device. In particular, the assembly characteristics of a large display device with a plurality of display panels may be improved.
2. Discussion of the Related Art
With rapid development of display devices, slim and light display devices with improved performance have been preferred. Cathode ray tubes (CRTs) have advantages in performance and price but disadvantages based on their size, weight, and portability.
Liquid crystal display devices (LCDs) are considered as replacement for CRTs because LCDs are slimmer and light weight and have lower power consumption. LCDs are used as display devices in information processing devices, such as home computers. In LCDs, a specific molecular arrangement of liquid crystals is changed when a predetermined voltage is applied thereto. Light transmittance can be adjusted using the change in the molecular arrangement of the liquid crystals. In this way, the LCD displays an image.
Although LCDs have been widely used in notebook computers and household television sets, their applications are expanding to larger public display devices. LCDs may be used for large billboards for a variety purposes, such as a stadium scoreboard or “jumbotron.” As a result, the LCDs must be large in size so that a number of people can view a clear image from a large distance. In LCDs, it may be difficult to make a large glass substrate, and failure may occur in the liquid crystals. In addition, the fabrication of the large display device requires larger processing equipment, leading to the increase in a manufacturing cost of the display device. Since signal lines of the LCD become longer, pixels become more difficult to drive and image quality may be degraded.
A tiling LCD has been developed which may meet a demand for a new display device and be manufactured at a low cost. A tiling LCD may be a plurality of smaller LCDs that are combined side-by-side into a larger LCD. The smaller LCDs may be referred to as tiles that are combined to form the tiling LCD. FIG. 1 is a perspective view of a related art LCD, and FIG. 2 is a cross-sectional view taken along line I-I′ of FIG. 1. Specifically, FIG. 2 is a cross-sectional view of edge portions of liquid crystal display modules.
As shown in FIG. 1, a related art large LCD can be manufactured by sequentially arranging first to fourth liquid crystal display modules 10, 20, 30 and 40. As shown in FIG. 2, the related art liquid crystal display modules include liquid crystal panels 11 and 21 displaying an image, backlight units 15 and 25 supplying light to the liquid crystal panels 11 and 21, bottom cases 17 and 27 receiving the backlight units 15 and 25, and top cases 19 and 29 attached to the bottom cases 17 and 27 to fix the liquid crystal panels 11 and 21, respectively. The backlight units 15 and 25 include light sources 16 and 26, respectively. The backlight units 15 and 25 further include guide panels 31 and 32 receiving the liquid crystal panels 11 and 21 and various optical films 13 and 23, respectively.
The LCD 50 has an active area (AA) where an image is displayed and a non-active area NA where no image is displayed. The non-active area NA is outside of the active area AA for each display module. The non-active area NA between LCD modules is defined as the width k. As shown in FIG. 2, the non-active area between module 40 and module 30 is the width k. Likewise, the width between modules 10 and 20, 10 and 40, and 20 and 30 are all width k. The non-active area NA at the outer edge portions of the liquid crystal display modules 10, 20, 30 and 40 is approximately half of width k.
Therefore, a non-active area NA with a large width k exists between the first to fourth liquid crystal display modules 10, 20, 30 and 40. The wide non-active area NA is an obstacle to maximizing the image quality of the display. The non-active areas may affect the continuity of an image shown on a tiled LCD display device.